Panic with yaml.Strict() and an inlined map #810
Description
Describe the bug
When unmarshalling using yaml.Strict()/yaml.DisallowUnknownFields()1 and the target structure includes an inlined map, it panics:
Traceback
panic: reflect: NumField of non-struct type map[string]interface {}
goroutine 1 [running]:
reflect.(*rtype).NumField(0x0?)
/usr/local/go-faketime/src/reflect/type.go:791 +0x59
github.com/goccy/go-yaml.structFieldMap({0x5a9e68, 0x547540})
/tmp/gopath1908489966/pkg/mod/github.com/goccy/go-yaml@v1.18.0/struct.go:115 +0xd7
github.com/goccy/go-yaml.(*Decoder).deleteStructKeys(0xc0001400e0, {0x5a9e68, 0x547540}, 0xc00012b020)
/tmp/gopath1908489966/pkg/mod/github.com/goccy/go-yaml@v1.18.0/decode.go:669 +0x8d
github.com/goccy/go-yaml.(*Decoder).decodeStruct(0xc0001400e0, {0x5a6ed8, 0x6bcea0}, {0x548440?, 0xc00011c0b0?, 0x0?}, {0x5a7a98, 0xc000116340})
/tmp/gopath1908489966/pkg/mod/github.com/goccy/go-yaml@v1.18.0/decode.go:1384 +0x1bb4
github.com/goccy/go-yaml.(*Decoder).decodeValue(0xc0001400e0, {0x5a6ed8, 0x6bcea0}, {0x548440?, 0xc00011c0b0?, 0xc00011c0e0?}, {0x5a7a98, 0xc000116340})
/tmp/gopath1908489966/pkg/mod/github.com/goccy/go-yaml@v1.18.0/decode.go:961 +0x1998
github.com/goccy/go-yaml.(*Decoder).decode(0xc0001400e0, {0x5a6ed8, 0x6bcea0}, {0x537640?, 0xc00011c0b0?, 0x47158f?})
/tmp/gopath1908489966/pkg/mod/github.com/goccy/go-yaml@v1.18.0/decode.go:1964 +0x23a
github.com/goccy/go-yaml.(*Decoder).DecodeContext(0xc0001400e0, {0x5a6ed8, 0x6bcea0}, {0x537640?, 0xc00011c0b0?})
/tmp/gopath1908489966/pkg/mod/github.com/goccy/go-yaml@v1.18.0/decode.go:1996 +0x151
github.com/goccy/go-yaml.UnmarshalContext({0x5a6ed8, 0x6bcea0}, {0xc00013e018, 0x15, 0x15}, {0x537640, 0xc00011c0b0}, {0xc00011c0b8, 0x1, 0x1})
/tmp/gopath1908489966/pkg/mod/github.com/goccy/go-yaml@v1.18.0/yaml.go:207 +0x219
github.com/goccy/go-yaml.UnmarshalWithOptions(...)
/tmp/gopath1908489966/pkg/mod/github.com/goccy/go-yaml@v1.18.0/yaml.go:201
To Reproduce
https://go.dev/play/p/e__-FOekQ_4
Expected behavior
Either work (as did yaml.v3) or give an error message ("Unmarshalling into a map with DisallowUnknownFields is not meaningful").
I would argue for "making it work", because I want to only allow fixed keys for most of the structure, while having some sub-structures that allow arbitrary key/values, like:
type Config struct {
OptionA int
OptionB string
Details struct {
RoundRobin bool
Hosts map[string]string `yaml:",inline"`
}
}Version Variables
- Go version: 1.25
- go-yaml's Version: v1.18.0
Footnotes
-
Having two options doing exactly the same without the documentation saying so (or one being deprecated) is odd. ↩